Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Intermediary Metabolism > Fatty Acid catabolism - Lecture 1 > Flashcards

Fatty Acid catabolism - Lecture 1 Flashcards

1
Q

90% of dietary lipids are ___________.

A

triacylglycerols

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Fatty acids are composed of what?

A

Long hydrophic HC chain (highly reduced) and a carbozylic polar group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the different sources of fat available for oxidation?

A

1 - Dietary fat
2 - Excess dietary fat stores in adipose tissue
3 - Excess carbohydrate calories converted to fat in the liver and transported to adipose tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the functions of fat?

A
  • Stored fat acts as a major source of energy when there are no carbs available.
  • Serves as a supply of FAs required for cellular function
  • Provides insulation and complexion to the body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

FA are amphipolar and act as ________.

A

detergents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do excess carbs become fat?

A

Excess carbs, go to liver, converts glucose to fat via glycolysis, then PDC, then acetyl-CoA is stored as fat in adipocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What transports fat from the liver to adipose tissues?

A

LDL and HDL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why are fats important for cellular function?

A

Lipid bilayer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the issues with being too lean, i.e. low fat stores?

A

1 - Look sick - bad complexion
2 - Feel cold due to lack of insulation
3 - Cannot afford to starve since there are not fat stores to sustained survival

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a fatty acid glycerol?

A

3 fatty acids bound to a glycerol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

A fully saturated fatty acid glycerol will be ______.

A

Solid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does unsaturation affect the structure of a fat molecule?

A

Change in conformation, no more stacking of fatty acids, generally liquid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is hydrogenation

A

Artificial saturation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

After triacylglercyrols are ingested, they are present in the form of _____ ______.

A

oil droplets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the liver produce to emulsify fat? Where is it stored? Where is it released?

A

Liver produces bile acids
Collect in the gallbladder
Released into the small intestine to emulsify fat.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

A challenge in the physiological system is that the pipeline is _____-_____, but we need to absorb fat and transport it.
What is another issue with fat digestion?

A

water-based

All our enzymes are water based, work in aqueous solution. Fat doesnt mix with water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

When triacylglycerols are digested, what do they produce? What are the dangers of this?

A

Produce glycerol (harmless) and FAs (detergents)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How are the fatty acids, acting like detergents, kept in check?

A

Fatty acid binding proteins keep the detergents inactive.

These are only released when needed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the purpose of bile acids?

A

Emulsify fat so it can be digested by enzymes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are bile acids?

A

Amphipathic (polar and non-polar structures), detergent-like molecules that are synthesized in the liver that help to solubilize or emulsify triglycerides in the small intestine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are pancreatic lipases?

A

Pancreatic enzymes that catalyze the hydrolysis of fat to release fatty acids and glycerol in the intestine.

22
Q

What do both bile acids and fatty acid binding proteins do?

A

Facilitate absorption of lipids in the intestine.

23
Q

What are intestinal fatty acid binding proteins (-FABP)?

A

Proteins present inside the intestinal cells, they bind to fatty acids and protect cells from the detergent-like behaviour of FAs.

24
Q

What are chylomicrons?

A

Transport granules, cholesterol and lipids from intestine to liver and adipose tissue via blood.

25
Q

What are lipoprotein lipases?

A

These enzymes are present in the capillaries or the peripheral tissues. They digest tryglycerides into FA and glycerol.

26
Q

What are bile acids?

A

Detergent like molecule produced in the liver to help in digestion of fat in the intestine (emulsify fat)

27
Q

What are pancreatic lipases?

A

Synthesized in the pancreas and then secreted into the SI.

Enzymes that digest fat into FA and glycerol

28
Q

What do both bile acids and FABP do?

A

FABP and bile acid bind to fat molecules and keep their concentration low to prevent damage to the wall of the intestines or cells.

29
Q

What are I-FABP?

A

FABP in the intestinal cells that prevent fat from causing problems.

30
Q

What are chylomicrons?

A

Lipoproteins that can bind fat molecules and cholesterol and are assembled in the intesetinal cells.
Brings to different tissues and liver.

31
Q

What are lipoprotein lipases?

A

Located in tissue capillaries, digests fat into FA and glycerol which can be absorbed by the tissues.

32
Q

What is the hormone dependent lipase?

A

When starving, lipase activated dependent on hormones, will digest fat in tissues.

33
Q

Provide the summary of how fat is absorbed.

A

1 - Fat is ingested in the diet
2 - Bile salts emulsify ingested fats
3 - Pancreatic lipases digest triglycerides into FAs and glycerol which are absorbed into the intestinal cells and immediately converted back to triacylglycerol.
4 - Fat is loaded onto apolipoprotein C-2, along with cholesterol to form a chylomicron
5 - Chylomicron is shuttled into the blood and goes to the peripheral tissue
6 - Lipoprotein lipases digest the chylomicron into FA and glycerol, which is absorbed into the tissues
7 - In muscles, this is immediately catabolized
- in adipocytes, this is converted back to fat and stored as fat in water-soluble micelles, can also be used for energy

34
Q

What does a chylomicron contain?
How does a chylomicron have affinity for fatty tissues?
Where are chylomicrons generated?
What do they transport?

A

Cholesterol, lipoproteins and triacylglycerols.

Receptor that has affinity for fatty tissues to activate capillary lipase.

Generated in intestinal cells.
Transports fat in the blood to all the tissues.

35
Q

All DLs are generated where?

A

Liver

36
Q

What are the two sources of fat?

A

SI and liver

37
Q

What do lipoproteins carriers contain?

A

Lipoprotein, tryglycerides, cholesterol

38
Q

What is VLDL?

A

Produced in the liver
Loaded with the max amount of fat and cholesterol.
Goes out into the blood to different tissues and can deposit fat to hungry, metabolically active tissues.

39
Q

When does VLDL remain as VLDL?

A

When overeating and not burning any fat.

40
Q

When does VLDL become HDL?

A

When the tissues, like the muscles are active, such as when exercising, VLDL dumps off its fat and becomes HDL.

41
Q

What does HDL do?

A

Hungry for hydrophobic molecules, will go through the blood vessels back to the liver and mop up the arteries.

42
Q

Do chylomicrons go back to the intestine?

A

No, go back to the liver and get digested there

43
Q

What does blood plasma look like after a meal?

A

Turbid due to chylomicrons.

44
Q

Suppose that after a fast, blood plasma still looks like blood plasma after just eating. Why?

A

VLDL makes it turbid
Liver has to adjust and reload fat onto own vehicle.
Releases VLDL but, stores are full since not exercising,
So, lots of fat still in the blood.

45
Q

The liver takes unused fat from the _________ and fat from excess ________ and loads it onto lipoproteins to generate _______, which is thrown back into the blood.
If the tissues are active, they will accept fat and ______ will be converted to ______.
Circulating ______, will then mop up fatty deposition (________) in the blood _______. _____ then goes back to liver.

A 
chylomicron
glucose
VLDL
VLDL
HDL
HDL
cholesterol
vessels
46
Q

What was a clever way to reduce cholesterol?

A

Designed bacteria that can be taken as a probiotic that destroys bile acid.
Liver then keeps taking cholesterol to produce new bile acid.

47
Q

In the intestine, there are bile acid binding proteins and fatty acid binding proteins. Why?

A

These would be detergents otherwise.

48
Q

Lots of HDL indicates that the person is ______ ___.

A

burning fat (tissues and muscles are taken in fat)

49
Q

Describe the pathway to utilize stored fat.

A

Low blood glucose and energy trigger the secretion of glucagon (and epinephrine in emergency situations).
This activates a G-protein, leading to activation of adnylate cyclase.
This produces cAMP, which activates PKA.
PKA phosphorylates and activates triacylglycerol lipase.
This causes release of fatty acids into the blood, which get bound by serum albumin.
FAs are then transported to the muscle tissues.
FA undergoes b-oxidation of FA to produce acetyl-coA

PKA also phosphorylates adipolipin, which causes it to get dissolved in solution and allow micellles to be free.

50
Q

How is glycerol utilized after digestion by lipase?

A

Glycerol can be converted to glycerol-3-phosphate and then to DHAP. DHAP is converted to GAP by reaction 5 of glycolysis (triose phosphate isomerase) and then enters the GAPDH reaction directly.

51
Q

How is glycerol converted to G3P?

A

By glycerol kinase

52
Q

How is G3P converted to DHAP?

A

G3P DH

Intermediary Metabolism (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions